static IPv6 config on OVH dedicated server

Discussion:

Piotr Isajew

2021-04-09 20:28:09 UTC

Hi,

I'm struggling to configure IPv6 for my fresh OpenBSD 6.8
installation running on OVH (soyoustart.com) dedicated server.

What I get from the ISP is the /64 address pool.
OVH requires static configuration with gateway outside of the
assigned subnet. According to their docummentation:

The default gateway for your IPv6 block (IPv6_GATEWAY) is always
xxxx.xxxx.xxxx.xxFF:FF:FF:FF:FF.

For example:

The IPv6 address of the server is 2607:5300:60:62ac::/64. The
IPv6_GATEWAY will therefore be 2607:5300:60:62FF:FF:FF:FF:FF.

My problem is how to properly configure the route to their
gateway. I'm trying i.e.:

ifconfig ix0 inet6 alias 2607:5300:60:62ac:: prefixlen 64
route add -inet6 -host 2607:5300:60:62FF:FF:FF:FF:FF -llinfo \
-link -iface ix0

but it doesn't work:

ping6 2607:5300:60:62FF:FF:FF:FF:FF

ping6: sendmsg: Invalid argument

I know, that if I shrink the prefix to 56, the gateway starts to
be directly reachable and then it responds to pings. I just
wonder if there is a way to make the gateway reachable with
proper prefix on the interface.

Eric JACQUOT

2021-04-09 22:05:45 UTC

Permalink

Too fast

You will never reach an outside gateway.

--
Eric JACQUOT
--------------------------------
De : Eric JACQUOT
Envoyé : vendredi 9 avril 2021 23:55
À : Piotr Isajew; ***@openbsd.org
Objet : Re: static IPv6 config on OVH dedicated server

Hi Piotr,

You have to configure your if with a /56 mask and then you will be able reach the ipv6 gateway.

Remember to accord your pf rules to allow required icmpv6 types.

Cheers,

--
Eric JACQUOT
--------------------------------
De : Piotr Isajew <***@yahoo.com>
Envoyé : vendredi 9 avril 2021 22:59
À : ***@openbsd.org
Objet : static IPv6 config on OVH dedicated server

Hi,

I'm struggling to configure IPv6 for my fresh OpenBSD 6.8
installation running on OVH (soyoustart.com) dedicated server.

What I get from the ISP is the /64 address pool.
OVH requires static configuration with gateway outside of the
assigned subnet. According to their docummentation:

The default gateway for your IPv6 block (IPv6_GATEWAY) is always
xxxx.xxxx.xxxx.xxFF:FF:FF:FF:FF.

For example:

The IPv6 address of the server is 2607:5300:60:62ac::/64. The
IPv6_GATEWAY will therefore be 2607:5300:60:62FF:FF:FF:FF:FF.

My problem is how to properly configure the route to their
gateway. I'm trying i.e.:

ifconfig ix0 inet6 alias 2607:5300:60:62ac:: prefixlen 64
route add -inet6 -host 2607:5300:60:62FF:FF:FF:FF:FF -llinfo \
-link -iface ix0

but it doesn't work:

ping6 2607:5300:60:62FF:FF:FF:FF:FF

ping6: sendmsg: Invalid argument

I know, that if I shrink the prefix to 56, the gateway starts to
be directly reachable and then it responds to pings. I just
wonder if there is a way to make the gateway reachable with
proper prefix on the interface.

Piotr Isajew

2021-04-10 04:41:27 UTC

Permalink

Post by Eric JACQUOT
Too fast
You will never reach an outside gateway.

Thanks Eric. Actually it works with /56 :)

- gateway "starts to be" in the same subnet then and is directly
reachable without a need to tweak the routing table
- when I add it as a default gateway I am able to reach the
outside network, also my host responds to ping6 from the
Internet

Eric JACQUOT

2021-04-09 21:55:37 UTC

Permalink

Hi Piotr,

You have to configure your if with a /56 mask and then you will be able reach the ipv6 gateway.

Remember to accord your pf rules to allow required icmpv6 types.

Cheers,

--
Eric JACQUOT
--------------------------------
De : Piotr Isajew <***@yahoo.com>
Envoyé : vendredi 9 avril 2021 22:59
À : ***@openbsd.org
Objet : static IPv6 config on OVH dedicated server

Hi,

I'm struggling to configure IPv6 for my fresh OpenBSD 6.8
installation running on OVH (soyoustart.com) dedicated server.

What I get from the ISP is the /64 address pool.
OVH requires static configuration with gateway outside of the
assigned subnet. According to their docummentation:

The default gateway for your IPv6 block (IPv6_GATEWAY) is always
xxxx.xxxx.xxxx.xxFF:FF:FF:FF:FF.

For example:

The IPv6 address of the server is 2607:5300:60:62ac::/64. The
IPv6_GATEWAY will therefore be 2607:5300:60:62FF:FF:FF:FF:FF.

My problem is how to properly configure the route to their
gateway. I'm trying i.e.:

ifconfig ix0 inet6 alias 2607:5300:60:62ac:: prefixlen 64
route add -inet6 -host 2607:5300:60:62FF:FF:FF:FF:FF -llinfo \
-link -iface ix0

but it doesn't work:

ping6 2607:5300:60:62FF:FF:FF:FF:FF

ping6: sendmsg: Invalid argument

I know, that if I shrink the prefix to 56, the gateway starts to
be directly reachable and then it responds to pings. I just
wonder if there is a way to make the gateway reachable with
proper prefix on the interface.

Fernando Gont

2021-04-10 04:05:08 UTC

Permalink

Piotr,

Post by Piotr Isajew
The default gateway for your IPv6 block (IPv6_GATEWAY) is always
xxxx.xxxx.xxxx.xxFF:FF:FF:FF:FF.
The IPv6 address of the server is 2607:5300:60:62ac::/64. The
IPv6_GATEWAY will therefore be 2607:5300:60:62FF:FF:FF:FF:FF.

Then create net routes for both:

* 2607:5300:60:62ac::/64
* 2607:5300:60:62FF::/64

on the same interface. i.e., both networks are on-link, and things will
work.

Thanks,

--
Fernando Gont
e-mail: ***@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492

Piotr Isajew

2021-04-10 05:08:41 UTC

Permalink

Post by Eric JACQUOT
Piotr,

* 2607:5300:60:62ac::/64
* 2607:5300:60:62FF::/64
on the same interface. i.e., both networks are on-link, and things will
work.

Thanks, but this doesn't work for me. I did:
- configure my interface with /64 prefix len
- add both /64 IPv6 blocks to the routing table:

route add -inet6 <<ipv6_block>> -link -iface ix0

gateway doesn't respond to ping6 (I get sendmsg: Invalid
argument)

For now it seems that the only working configuration is to set my
interface prefix len to 56.

Eric JACQUOT

2021-04-11 22:13:39 UTC

Permalink

Hi Piotr,

-----Message initial-----

Envoyé: vendredi 9 avril 2021 22:59
Sujet: static IPv6 config on OVH dedicated server
Hi,
I'm struggling to configure IPv6 for my fresh OpenBSD 6.8
installation running on OVH (soyoustart.com) dedicated server.
What I get from the ISP is the /64 address pool.
OVH requires static configuration with gateway outside of the
The default gateway for your IPv6 block (IPv6_GATEWAY) is always
xxxx.xxxx.xxxx.xxFF:FF:FF:FF:FF.
The IPv6 address of the server is 2607:5300:60:62ac::/64. The
IPv6_GATEWAY will therefore be 2607:5300:60:62FF:FF:FF:FF:FF.

A decade ago, I tried to configure OVH ipv6 and give up after an headhache to use an ugly /56.
I never try again to deal with a /64 and an outside gateway since your mail.
Then I tried again with a fucking headache. But thanks to you. I solved my misconfigured problem.

Before you test, stay with your /56 and try to list the mac address of your default gateway with :

# ndp -a

You will see the MAC address you will need for your /etc/hostname.if (this is an example for the ip6 part)

...
inet6 2607:5300:60:62ac:: 64
!route add -inet6 2607:5300:60:62ff:ff:ff:ff:ff/128 -link -static -iface ix0
!route add -inet6 default 2607:5300:60:62ff:ff:ff:ff:ff
#replace XX:XX:XX:XX:XX:XX with the gw mac address :
!ndp -s 2607:5300:60:62ff:ff:ff:ff:ff XX:XX:XX:XX:XX:XX proxy
#EOF

This will work as expected.

Cheers,

Eric JACQUOT

2021-04-11 22:19:13 UTC

Permalink

Forgot this. 1 hour later It sucks again
. What a fucking network :(

-----Message initial-----

Envoyé: lundi 12 avril 2021 0:13
Sujet: RE: static IPv6 config on OVH dedicated server
Hi Piotr,
-----Message initial-----

A decade ago, I tried to configure OVH ipv6 and give up after an headhache
to use an ugly /56.
I never try again to deal with a /64 and an outside gateway since your mail.
Then I tried again with a fucking headache. But thanks to you. I solved my
misconfigured problem.
Before you test, stay with your /56 and try to list the mac address of your
# ndp -a
You will see the MAC address you will need for your /etc/hostname.if (this
is an example for the ip6 part)
...
inet6 2607:5300:60:62ac:: 64
!route add -inet6 2607:5300:60:62ff:ff:ff:ff:ff/128 -link -static -iface ix0
!route add -inet6 default 2607:5300:60:62ff:ff:ff:ff:ff
!ndp -s 2607:5300:60:62ff:ff:ff:ff:ff XX:XX:XX:XX:XX:XX proxy
#EOF
This will work as expected.
Cheers,